Permian

The Permian is a geologicalperiod which started about 299 million years ago (mya), and ended about 252 mya. It is the last period of the Paleozoicera, and ended in the largest mass extinction known to science.

The climate in the Permian was quite varied. At the start of the Permian, the Earth was still at the grip of an Ice age from the Carboniferous. Glaciers receded around the mid-Permian period as the climate gradually warmed, drying the continent's interiors.[2] In the late Permian period, the drying continued although the temperature cycled between warm and cool cycles.[2]

The Permian was also a period of adaptive radiation in insects. Beetles (Coleoptera) appeared; so did flies (Diptera). 22 out of a total of 36 known orders of insects are known from the Permian. Some became extinct in the end-Permian event, but more radiation followed in the Mesozoic. Insects were probably, by the end of the Permian, the largest phylum,[4] in terms of number of species.[5]

All the major land masses were collected together in the super-continentPangaea. At the end of the period, the greatest flood basaltlava flows in the Phanerozoic raised world temperatures, and damaged the environment. These formed the extensive Siberian traps. The causes of the Permian/Triassic extinction event are not yet agreed between scientists.[9]Trilobites, once a dominant life-form in the ocean, became extinct, together with 90% of all marine species.